I am using Px4 with, Qground control on Unbutu-mate18.04 &ROS Kinetic using Odroid,

I am trying to use MAV_CMD_DO_SET_SERVO to send PWM commands to AUX1 (channel 9). But unable to find the right protocol structure to do it.

Aim: I want to integrate activating and Deactivating magnet into a FCU code that I have built (set Magnet at AUX1 normally operated through RC)

msg_hi = self.vehicle.message_factory.command_long_encode( 0, 0, # target_system, target_command mavutil.mavlink.MAV_CMD_DO_SET_SERVO, # command 0, 8, # servo number 2006, # servo position 0, 0, 0, 0, 0)

Here, I know here in this example I have tried using similar dronekit function not knowing how I can do using MAVROS, Pleaseee guide me if any alternative ways how I can do it, I am looking how to achieve the Task using Mavros?

I don't see my drone responding even after sending self.vehicle.send_mavlink(msg_hi), checked the AUX1 pin with Oscilloscope, but I don't see any fluctuating signal..

!/usr/bin/python

import rospy as rp import threading

from dronekit import connect, VehicleMode from pymavlink import mavutil

from std_msgs.msg import Int8 from sensor_msgs.msg import Joy from geometry_msgs.msg import PoseStamped, TwistStamped

class magdroneControlNode():

def init(self): rp.init_node("magdrone_deploy")

# Connect to the Vehicle
rp.loginfo('Connecting to Vehicle')
self.vehicle = connect('/dev/ttyUSB0', wait_ready=True, baud=921600)

# Set up Subscribers
self.joy_sub = rp.Subscriber("/joy", Joy, self.joy_callback, queue_size=1)

# Create thread for publishers
self.rate = 30
t = threading.Thread(target=self.send_commands)
t.start()

rp.spin()

def joy_callback(self, data):

Button Controls

if data.buttons[0] == 1.0:
    rp.loginfo("Mission set to 1 - Deploying Sensor")
    self.mission_id = 1

if data.buttons[1] == 1.0:
    rp.loginfo("Mission set to 2 - Retrieving Sensor and Exiting")
    self.mission_id = 2

''' Magnet Control '''

def engage_magnet(self): msg_hi = self.vehicle.message_factory.command_long_encode( 0, 0, # target_system, target_command mavutil.mavlink.MAV_CMD_DO_SET_SERVO, # command 0, 8, # servo number 2006, # servo position 0, 0, 0, 0, 0)

msg_neut = self.vehicle.message_factory.command_long_encode(
        0, 0,   # target_system, target_command
        mavutil.mavlink.MAV_CMD_DO_SET_SERVO, # command
        0,
        8,    # servo number
        1500, # servo position
        0, 0, 0, 0, 0)

# Send command
self.vehicle.send_mavlink(msg_hi)
rp.loginfo("Magnet Engaged")
time.sleep(5)
self.vehicle.send_mavlink(msg_neut)
rp.loginfo("Magnet in Neutral")
self.docked = True

def disengage_magnet(self): msg_low = self.vehicle.message_factory.command_long_encode( 0, 0, # target_system, target_command mavutil.mavlink.MAV_CMD_DO_SET_SERVO, # command 0, 8, # servo number 982, # servo position 0, 0, 0, 0, 0)

msg_neut = self.vehicle.message_factory.command_long_encode(
        0, 0,   # target_system, target_command
        mavutil.mavlink.MAV_CMD_DO_SET_SERVO, # command
        0,
        8,    # servo number
        1500, # servo position
        0, 0, 0, 0, 0)

# Send command
self.vehicle.send_mavlink(msg_low)
rp.loginfo("Magnet Disengaged")
time.sleep(5)
self.vehicle.send_mavlink(msg_neut)
rp.loginfo("Magnet in Neutral")
self.docked = False

''' Main Loop '''

def send_commands(self): rp.loginfo("Accepting Commands") r = rp.Rate(self.rate) while not rp.is_shutdown():

    if (self.mission_id == 1) & (not self.magnet_engaged):
        self.magnet_engaged = True
        t = threading.Thread(target=self.engage_magnet)
        t.start()

    if (self.mission_id == 2) & (self.magnet_engaged):
        self.magnet_engaged = False
        t = threading.Thread(target=self.disengage_magnet)
        t.start()
    r.sleep()

magdrone = magdroneControlNode()

mavlink / mavros

How to use MAV_CMD_DO_SET_SERVO with mavros? is there any alternate command to send control AUX1 port with PWM signal #1759

!/usr/bin/python

Button Controls